I have a couple of precautionary questions: is it safe to:
- update Electrum
- receive and send other transactions
while I have this 'Local' transaction hanging?
You can update your Electrum wallet. Updating the wallet will not affect the local transaction. And you can send and receive other transactions. When sending, I recommend not to use unconfirmed assets to avoid any misunderstandings. If you try to send unconfirmed coins, Electrum will warn you "This transaction will spend unconfirmed coins.".